Conventionally, ultrasonic diagnosing devices are known, which derive information of a cartilage based on reflection echoes caused by ultrasonic waves transmitted toward the cartilage, so as to analyze a state of the cartilage. For example, Patent Document 1 discloses an ultrasonic diagnosing device which extracts a boundary between a knee cartilage and a different tissue adjacent to the cartilage by extracting an edge of an echo level from echo signals of ultrasonic beams transmitted to the cartilage. Further, a shape of the cartilage is extracted based on the extracted boundary.